Saturday, December 3, 2016

Yamaha PM1000 Transistor Mike Preamp wild Racking Projects

Here are some 'interesting' Yam projects

This is four channel rack job for a Italian customer

Below shows my placing the out transformer in the back
of the module so each one had both in/out transformers inside 

They had to be mounted on a frame  that was going into a wood box

Four XLR input jacks, and four TRS output jacks

 The 1/4" DI in jacks are at the bottom of the channels
You can see a black cable going to one jack

I added a passive EQ from a old tube stereo console
This allowed the owner to be able to patch it in to add some
Vintage 'Smooth' tone to any sound

Below shows measuring things out

The below shows measuring and drilling out the Hammond
16" wide by 8" deep by 3-1/2" high box for two rack jobs at a time
This was one way to keep up with orders and make sure both were
drilled out and all parts placed in the same places.

I replaced the output transistors with lower gain bigger power
transistors and increased the idle to get more power, less noise and
a much bigger, tighter sound, and nice round tone Hi-Fi bass

This unit used EDCOR 600 ohm line out transformers
These 'step-up' the signal three times more for up to +28DB levels
out, and the line stage runs at three times less gain for less noise 


Any questions or interest in projects?

George at
Vista, CA 92084

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